1. Field of Invention
The present invention is related to a developing device and an image forming apparatus having the developing device such as a laser printer.
2. Description of Related Art
In a laser printer disclosed in U.S. Pat. No. 6,041,203, a developing cartridge storing toner is detachably mounted in the printer. The developing cartridge includes a toner box for storing toner and a developing roller for bearing a thin layer of toner. An agitator is arranged in the toner box for agitating and transporting the toner.
A supply roller is arranged in the developing cartridge for supplying the toner that is transported from the agitator to the developing roller. The agitator, the supply roller and the developing roller are arranged rotatably.
The developing cartridge further comprises a gear mechanism for transmitting driving force to the developing roller, the supply roller and the agitator.
The invention provides a developing device and an image forming apparatus wherein the relative positions of a developing roller drive gear, supply roller drive gear and an input gear can be determined with precision and more particularly, to a developing device and an image forming apparatus wherein the relative positions of a developing roller and supply roller can be determined with high precision.
According to one aspect of the invention, a developing device is provided with a housing and a separate holder, mounted to an outside sidewall of the housing, integrally formed with supports that support a developing roller and a supply roller.
Accordingly, the developing device and image forming apparatus are driven stably and the contact condition of the developing roller and supply roller is also stable, and thus, image quality is improved.